By Ben Hirschler

LONDON (Reuters) – European medicines regulators have issued a notice that an ingredient for a generic brain cancer drug made in China does not meet manufacturing standards, after inspectors were refused entry to a factory run by Jiangsu Yew Pharmaceutical Co. Ltd.

The incident, reported in a notice published this week on a database maintained by the European Medicines Agency, is the latest example of regulatory problems with bulk pharmaceutical substances manufactured in China. (Click for the notice)

It follows a scandal over tainted supplies of the widely used heart drug valsartan from Zhejiang Huahai Pharmaceutical, which led to dozens of recalls around the world of finished tablets containing the Chinese product.

U.S. officials have also recently recalled porcine thyroid active ingredient from China due to inconsistent quality.

In the latest case, Jiangsu Yew refused to allow a site inspection by Hungarian officials, acting on behalf of Europe’s drug regulatory system. The rebuttal led the EU authorities to determine that its supplies of temozolomide, used to treat brain tumors, did not comply with good manufacturing standards.

The company’s export director Henry Yang told Reuters via email that the inspection was refused because Jiangsu Yew only made an intermediate product, rather than an active pharmaceutical ingredient (API), so an audit was not required.

Manufacturers in China and India supply more than two-thirds of all bulk pharmaceutical substances used in medicines, industry executives estimate, with China accounting for the lion’s share.

In recent years, U.S. and European regulators have increased scrutiny of Asian drug factories following the adulteration of the blood thinner heparin, which sickened hundreds and caused the deaths of at least 81 Americans in 2007 and 2008.

(This version of the story has been refiled to add missing word “notice” in second paragraph)

(Reporting by Ben Hirschler; Editing by Jan Harvey)